I was quite surprised how different work was from school. There are a few specific considerations I never really see discussed:
- In school you can fail the entire class, (ie, all the students) which is less true at work. At work, you're just hiring your "section" of the bell curve, and insofar as being "successful" means "doing well at your job and not getting fired" then a C or D student can potentially be happily and gainfully employed indefinitely. They might have to take a less prestigious job, but they can find their niche and their place. This one really surprised me. You just don't have freedom of movement in school the way you do at work, and so anyone who is observant and hard working can pivot to a relatively-good situation for themselves. This just is not true at school.
- You get nearly endless chances to fail at work, and you usually have a PIP period of weeks or months to parachute to another job if you actually encounter failure. I know some people who have been failures for an entire 30-40 year career.
- If you're bad at writing essays in school, it doesn't matter; you simply need to write essays and getting better or worse at writing essays won't modify the number of essays you need to write. With work on the other hand you can specialize and minimize your weaknesses and play to your strengths. Yes, you can more easily change positions to accomplish this, but even within a single position you can just find ways to focus on the parts of the job you're best at and and excel at that area.
- Very, very few jobs have anything which resembles testing. In the real world you must understand _why_ certain things need to be done, but almost everyone has the opportunity to pause and look up the details via references. Testing really does not represent this whatsoever. It's also the case that some tasks at work will be done over and over again, and in real depth, and via this depth and repetition you will actually memorize things via real behavioral reward mechanisms that are just not possible in a classroom environment.
- You can always seek more clarification in the real world, and can even negotiate your own limitations. Your boss has asked you to do something? Have a conversation with them and explain the limitations in the approach and what sort of partial approach you think might work. This works great in the real world but is much, much more limited in a classroom environment.
I could go on, but I was honestly shocked when I got my first job and I was actually a pretty good employee. This has been true ever since, but I was screwing up in school all the time.